Pinch Analysis for Heat Integration of Pulverized Coke Chemical Looping Gasification Coupled with Coke-Oven Gas to Methanol and Ammonia

Abstract

Methanol and ammonia are important chemical materials in the chemical industry. During the production of methanol and ammonia, a large amount of waste heat is released. The waste heat can be used to save energy and reduce CO2 emissions. In this study, pinch analysis is used to design the heat exchanger network (HEN) of pulverized coke (PC) chemical looping gasification coupled with coke-oven gas (COG) to methanol and ammonia (PCCLHG-CGTMA). The heat integration process is accomplished in two ways, as mentioned below. (1) The HENs in each of the three heat exchange units are designed individually; (2) the HENs of the three heat exchange units are treated as a whole and designed simultaneously. Compared to the HEN designed individually, when the HENs are designed as a whole, a total of 112.12 MW of hot and cold utilities are saved. In the HENs designed as a whole, the reduction in operating cost is sufficient to offset the increase in capital cost; the total annual cost (TAC) is reduced by 10.9%. These results reveal that the HENs designed as a whole have more scope for energy saving, which can be a reference for new HEN design and modification to realize more heat recovery and lower investment.

Process Integration Approach to the Methanol (MeOH) Production Variability from Syngas and Industrial Waste Gases

“…It is seen that MeOH synthesis utilizing COG had the highest hot utility requirements (50.28 MW), while it was the lowest (16.58 MW) in the case of the FG-based MeOH production process. The hot utility requirements were also reported in the rage of 5.00-108.33 MW by previous authors during the MeOH synthesis from various industrial waste gases [36,37]. In contrast, the cold utility requirement was the maximum for FG-based MeOH synthesis, and it was targeted as the lowest during the MeOH synthesis from SG.…”